Categorical Graphic
Probabilistic Tornado Graphic
Probability of a tornado within 25 miles of a point. Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point.
Probabilistic Damaging Wind Graphic
Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point. Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point.
Probabilistic Large Hail Graphic
Probability of hail 1" or larger within 25 miles of a point. Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point.

   SPC AC 150539
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1139 PM CST WED DEC 14 2011
   
   VALID 151200Z - 161200Z
   
   ...NO SVR TSTM AREAS FORECAST...
   
   ...SYNOPSIS...
   IN THE MID LEVELS...A CONUS-FULL-LATITUDE TROUGH...PRESENTLY
   EXTENDING FROM THE UPPER MS VALLEY SWD/SWWD TOWARD SRN AZ...WILL
   BECOME INCREASINGLY SHEARED AND DECOMPOSE INTO A NRN VORT MAX
   SWINGING THROUGH THE NERN STATES AND A SRN VORT MAX PROGRESSING
   ENEWD FROM THE SWRN STATES INTO PARTS OF THE SRN PLAINS. THE
   STRONGEST MID-LEVEL HEIGHT FALLS /OVER 100 METERS PER 12 HRS AT 500
   MB/ WILL LEAD THE FORMER FEATURE...WITH MORE MODEST HEIGHT FALLS
   LEADING THE LATTER. MEANWHILE...AT THE SFC...AN EXTENSIVE...
   NE-SW-ORIENTED COLD FRONT WILL SHIFT SEWD ACROSS PORTIONS OF THE ERN
   CONUS. OVER THE WRN STATES...DEEP-LAYER LOW PRESSURE WILL SHIFT
   SSEWD OVER PARTS OF CA.
   
   ...CNTRL/ERN TX ENEWD INTO SWRN KY AND MIDDLE TN...
   A PREFRONTAL ZONE OF SFC DEWPOINTS FROM THE MIDDLE 50S TO THE MIDDLE
   60S AND AN ASSOCIATED LOW-LEVEL THETA-E AXIS WILL SHIFT EWD IN
   CONCERT WITH THE PROGRESSIVE FRONT...YIELDING A WEDGE-SHAPED SECTOR
   OF MARGINAL INSTABILITY. WITH ANY APPRECIABLE DEEP-LAYER FORCING FOR
   ASCENT SPATIALLY WELL REMOVED FROM THIS SECTOR...CONVECTION WILL
   PRIMARILY BE CONFINED TO THE SFC FRONT. DESPITE THEIR LARGE
   MAGNITUDES...DEEP-LAYER SHEAR VECTORS WILL LARGELY BE ORIENTED
   PARALLEL TO THE BOUNDARY...SUGGESTING THAT ANY INITIALLY
   SURFACE-BASED CONVECTION WOULD QUICKLY BECOME UNDERCUT. THIS WILL
   GREATLY MITIGATE ANY SVR THREAT GIVEN THE SHARPENING TENDENCIES OF
   THE UNDERCUTTING SFC FRONT. FURTHERMORE...700-500-MB LAPSE RATES
   GENERALLY BELOW 7 C/KM WILL MITIGATE A MORE ROBUST CONVECTIVE
   POTENTIAL.
   
   ADDITIONALLY...THE AFOREMENTIONED SRN VORT MAX WILL PROGRESS
   ENEWD...WELL TO THE NW OF THE SFC FRONT. AMPLE DCVA AND MID-LEVEL
   WAA LEADING THIS COMPACT FEATURE WILL CONTRIBUTE TO THE DEVELOPMENT
   OF ELEVATED CONVECTION ACROSS CNTRL/NRN TX INTO SERN OK AND
   EVENTUALLY AR. IN THIS AREA...FORECAST SOUNDINGS FROM THE
   NAM...GFS...AND ETA-KF CONTROL MEMBER OF THE SREF INDICATE MUCAPE
   VALUES OF 100-200 J/KG FOR PARCELS ROOTED WITHIN THE
   750-650-MB-LAYER...WHICH WILL SUPPORT ISOLATED THUNDERSTORMS.
   
   ...ELSEWHERE...
   A FEW SPORADIC LIGHTNING STRIKES CANNOT BE ENTIRELY RULED OUT TO THE
   NE OF THE GENERAL THUNDER AREA -- I.E. AHEAD OF THE FRONT ACROSS THE
   OH VALLEY NEWD TOWARD NEW ENGLAND -- GIVEN THE LONG FETCH OF MOIST
   SWLY FLOW ALOFT...AREAS OF STRONG DEEP-LAYER ASCENT...AND NON-ZERO
   BUOYANCY. HOWEVER...COMPARATIVELY WEAKER LOW-LEVEL THETA-E IS
   FORECAST TO GREATLY LIMIT DESTABILIZATION...SUCH THAT 10-PERCENT
   THUNDER PROBABILITIES ARE NOT WARRANTED. ALSO...THE PREVIOUSLY
   MENTIONED DEEP-LAYER LOW PRESSURE SHIFTING SSEWD OVER CA IS EXPECTED
   TO BE DEVOID OF ANY BUOYANCY...WHICH WILL PRECLUDE THE DEVELOPMENT
   OF THUNDERSTORMS.
   
   ..COHEN/EDWARDS.. 12/15/2011
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z